The use of curable liquid polysulfide polymer based sealant compositions because of their durability and imperviousness to various agents which are known to affect other caulking compounds has long been practiced. For all their desirable properties, however, it has long been desired to improve the ability of these sealants to adhere more firmly to certain substrates such as glass in the presence of moisture and ultra-violet light. Improved adherence would allow more extensive use of these compounds in the fabrication of insulating glass units permitting the use of "formed in place" instead of "preformed" gaskets. The present invention relates to additives which supply greater adhesion to glass to the polysulfide polymer based caulks in which they are employed, to composltions formulated employing these additives, to processes for their preparation and use, and the articles of manufacture formed thereby.